Acoustic droplet vaporization and inertial cavitation thresholds and efficiencies of nanodroplets emulsions inside the focused region using a dual-frequency ring focused ultrasound

Shanshan Xu; Nan Chang; Rui Wang; Xiaodong Liu; Shifang Guo; Supin Wang; Yujin Zong; Mingxi Wan

doi:10.1016/j.ultsonch.2018.07.020

Acoustic droplet vaporization and inertial cavitation thresholds and efficiencies of nanodroplets emulsions inside the focused region using a dual-frequency ring focused ultrasound

Ultrason Sonochem. 2018 Nov:48:532-537. doi: 10.1016/j.ultsonch.2018.07.020. Epub 2018 Jul 18.

Authors

Shanshan Xu¹, Nan Chang¹, Rui Wang¹, Xiaodong Liu¹, Shifang Guo¹, Supin Wang¹, Yujin Zong², Mingxi Wan³

Affiliations

¹ The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
² The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China. Electronic address: yjzong@mail.xjtu.edu.cn.
³ The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China. Electronic address: mxwan@mail.xjtu.edu.cn.

PMID: 30080582
DOI: 10.1016/j.ultsonch.2018.07.020

Abstract

In this work, in order to develop a low-acoustic-intensity, high-efficiency and precise-treatment strategy, the vaporization of droplets and the inertial cavitation of vaporized microbubbles, using a dual-frequency focused ultrasound transducer, were investigated. The effect of a low frequency (LF), 1.1-MHz, sonication on droplet vaporization and the following inertial cavitation by the introduction of a high frequency (HF), 5-MHz, sonication was studied. It is shown that acoustic droplet vaporization (ADV) threshold is the lowest at dual-frequency sonication (LF of 18.9 W/cm² and HF of 4.1 W/cm²); moreover, the ADV efficiency is the highest at intensity threshold. The ADV area can be minimized to 2 mm² using a dual-frequency sonication (LF of 38.1 W/cm² and HF of 8.5 W/cm²). The IC area and efficiency can also be modulated using a dual-frequency sonication. Consequently, it can be concluded that in contrast to the single-frequency sonication, using the dual-frequency ultrasound, the vaporization of nanodroplets and the following inertial cavitation of the vaporized microbubbles can be modulated. Besides, a dual-frequency can result in the minimum ADV/IC area, lowest ADV/IC threshold, and highest ADV/IC efficiency.

Keywords: Acoustic droplet vaporization; Dual frequency insonication; Focal zone; Inertial cavitation; Threshold.